A. Field of the Invention
This invention relates to apparatus for announcing the presence of a person at the entrance of a structure or certain other localities to an occupant of the structure, and for communicating between the occupant and visitor. More particularly, the invention relates to signalling, voice communication, and video camera apparatus connectable to an existing doorbell button.
B. Description of Background Art
Frequently, an occupant of a structure such as an apartment building or private residence would like to communicate with a visitor, family member, or other such person, who has rung a doorbell located at the entrance to the structure. Having identified the person, the occupant can decide whether he or she wishes to admit the person to the building and/or to communicate further with the person. Thus, some apartment buildings are equipped at their entrances with an annunciator system comprising an array of doorbell buttons, and a microphone and loudspeaker allowing two-way voice communication between a visitor and the occupant of an apartment selected by the visitor. Such systems often include an electromechanical door release mechanism operable remotely by the apartment occupant, to let authorized individuals into the apartment building. Some annunciator systems also include a closed circuit television system including a camera viewing the building entranceway, the camera being connected to a television monitor viewable by occupants of the building.
Annunciator systems permitting two-way voice communications and one-way remote viewing usually require the installation of relatively long runs of interconnecting cables which must be installed in unobtrusive locations such as spaces between walls. Such cable installations can add considerable expense and inconvenience to the installation of such annunciator systems. That expense and inconvenience may at least partially explain the relatively small number of individual homes or small businesses having annunciator systems provided with voice and/or video transmission capability.
To eliminate the requirement for extensive cable installation procedures, some devices disclosed in the prior art utilize a radio-frequency (RF) link to carry two-way voice signals between a building entranceway and a monitoring station within the building. However, these prior art systems must still be connected to a source of electrical power. Some prior art annunciator systems possess a video as well as audio signal transmission capability, but require the use of cables connected between an annunciator station and a monitor station.
Typical prior art monitoring or annunciator systems of the type described above are described in the following United States Patents:
Moore, U.S. Pat. No. 3,480,727, Nov. 25, 1969, Closed Circuit Television Protection System:
Discloses a closed circuit television system for use in monitoring a door or other entranceway, to permit recognition of a visitor before the door is opened. The system includes wiring between a camera and loudspeaker located near the door, to a television monitor in which the filament of the picture tube is constantly energized by heating current, thereby allowing instant display of a scene viewed by the camera, when a switch is actuated. The direction of one-way voice communication between the camera loudspeaker/microphone and the monitor loudspeaker/microphone is selectable by a switch.
Desanti, U.S. Pat. No. 4,075,659, Feb. 21, 1978, Electronic Door Announcer:
Discloses an electronic door announcer for apartments of a multi-family dwelling having a community television antenna in which signals due to sound and video operation of the announcer are carried by at least part of the community antenna coaxial cable system, switching means for the individual apartments being connected into said coaxial cable system.
Cohn, U.S. Pat. No. 4,370,675, Jan. 25, 1983, Doorbell Actuated Television Security System:
Discloses a video security system with intercom activated by means of a doorbell. The video input to a remote camera is automatically presented on the video display of a television receiver upon activation of the doorbell while audio from the intercom's speaker microphone is output through the television receiver's speaker system. Following a predetermined time interval after doorbell actuation, the system automatically turns off. If the television receiver is on when the doorbell is actuated, the system automatically provides video camera and intercom information at the television, reverting to the received television signal mode of operation upon user selection.
Levinson, et al., U.S. Pat. No. 4,523,193, Jun. 1, 1985, Remote-Controlled Doorbell Signal Receiver:
Discloses a remote-controlled doorbell adapted for connection across the existing doorbell in a building having a wired doorbell system. A transmitter for generating an over-the-air radio signal is coupled across the wired doorbell so that the transmitter will be actuated in response to current flowing through the wired doorbell. A remote receiver coupled to sound producing means receives the over-the-air radio signal and actuates the sound producing means when the existing doorbell is energized.
Lefkowitz, U.S. Pat. No. 4,524,384, Jun. 18, 1985, Video and Audio Security System:
Discloses a video and audio system for monitoring an area, particularly an area adjacent a door. The system includes a video and audio assembly adapted to be mounted to a door and a video and audio console spaced from the door. Opening of the door is controlled by an electric door strike operated from the console. Both the console and the assembly include audio elements which permit simultaneous two-way communication. A limited number of conductors, one of which carry high voltage, couple the assembly and the console.
Chern, et al., U.S. Pat. No. 4,764,953, Aug. 16, 1988, Method and Apparatus for Remote Doorbell Answering:
Discloses an apparatus for providing remote answering of a doorbell that includes a circuit for receiving a doorbell signal indicative that a doorbell switch has been actuated. An autodialing circuit is coupled to and responsive to the receiving circuit and a telephone line for dialing a telephone number responsive to the doorbell signal. An alerting circuit generates an alert signal to be transmitted over the telephone line to the telephone number dialed by the autodialing circuit, so that the alert signal may alert a party answering the remote telephone to the fact that the party is responding to a doorbell rather than a normal telephone call. An audio speaker is physically situated near the doorbell switch, for reproducing audio signals from the telephone line which are generated at the remote telephone. An audio microphone is also physically situated near the doorbell switch, for generating electrical signals responsive to sounds made near the doorbell switch and transmitting the signals to the telephone line to the remote telephone. The apparatus further includes a switching network for coupling the door speaker and microphone to a local telephone set and a remote telephone set selectively in any combination.
Tatsumi, et al., U.S. Pat. No. 4,843,461, Jun. 27, 1989, Over-Door Interphone System Provided With a Night-Vision Monitoring Device:
Discloses an over-door interphone system for telephone communication between a master station unit, inside of a house, and a remote station unit, outside of an entrance door of the house, that is provided with a night-vision monitoring device. The system includes a television camera having a solid state camera sensitive to infrared light, and an infrared illuminator source comprising an array of infrared light emitting diodes.
Morotomi, et al., U.S. Pat. No. 4,959,713, Sep. 25, 1990, Home Automation System:
Discloses a home automation system in which a coaxial cable or other data bus is placed inside a home to connect an intercom unit and monitor camera for communication with visitors, to a conventional home television connected to the bus, thereby making it possible to output audio and video signals from the intercom unit and monitor camera on a conventional broadcast reception television.
The present invention was conceived of to provide an improved annunciator/monitoring system which eliminates the requirement for running electrical power and signal cables to a remote annunciator or monitoring station.